Three new species of Pythium, namely, P. oopapillum, P. emineosum and P. camurandrum are presented in this paper based on morphological descriptions and molecular phylogenetic characterisation. These new species were isolated from various ecological regions in Canada. They have unique morphological features in the genus Pythium, and form distinct clades in maximum parsimony analyses, which are also supported by maximum likelihood phylogeny using general time reversible model (GTR), and Bayesian inference (BI) phylogeny using Markov Chain Monte Carlo (MCMC) analysis methods. A comparative study of the new species with closely related taxa, their clade positions, and morphological features are described in this paper.